That's why a long-term sustainable fish farming experiment with a fish called Branzini (also known as European sea bass) is so promising.

Aquaculture is one key to supplying people with fish, and nearly half the fish consumed is now farmed rather than caught. But the most successful aquaculture experiments have not been entirely sustainable environmentally. And using smaller fish as the ground-up food for farming larger varieties has been decried as a huge waste.

Zohar is hoping to get funding to build a warehouse producing 200 tons of branzini a year.

And in the meantime, if you plan on having fish for dinner, don't shop for it at Trader Joe's, which garnered another "F" from Greenpeace for its lack of sustainable seafood at stores.

Instead, if you are standing at the fish counter wondering what's greenest, send a mail message to the Monterey Bay Aquarium FishPhone and you'll see whether your choice raises a red flag or is green for go.